Know Thyself

Cells of the pathogenic bacterium Proteus mirabilisclump together to form colonies that, on meeting other colonies, can distinguish self from foreigners. Proteusdetects, then deters, interlopers of the same species using polypeptide weapons called proticines. Gibbs et al.investigated the genetic basis of this self-non-self recognition system in Proteusand discovered a locus of six genes that seem to constitute general and specific recognition determinants, as well as accessory genes. Within infected hosts, P. mirabilisinfections are usually clonal, so this recognition system could be a way for an established clone to prevent superinfection by another clone and to avoid competition. K. A. Gibbs, M. L. Urbanowski, E. P. Greenberg, Genetic determinants of self identity and social recognition in bacteria. Science321, 256-259 (2008). [Abstract][Full Text]